import java.util.*;
public class RequestList {
	private ArrayList<Request> requestList;
	
	public RequestList() {
		requestList = new ArrayList<Request>();
	}
	
	/**
	 * This method adds a new request to the queue.
	 *
	 * @param reguest the new request to be added
	 */
	public void addPendingRequest(Request request) {
		int i = 0;
		while (i < requestList.size()) {
			if (request.getTime() < requestList.get(i).getTime()) {
				break;
			} else {
				i++;
			}
		}
		requestList.add(i, request);
	}
	
	/**
	* This method checks if there are any requests to summon an elevator
	*
	* @return true of there are any floors requesting an elevator, false otherwise
	*/
	public boolean hasPendingRequest() {
		if (requestList.size() > 0) {
			return true;
		} else {
			return false;
		}
	}

	/**
	 * This method determines the next request based on timestamp.
	 *
	 * @return the floor number of the next request
	 */
	public int getFirstPendingRequest() {
		return requestList.get(0).getCallingFloor();
	}
	
	/**
	* This method determines the next request based on proximity to the elevator's current floor.
	*
	* @param currentFloor the current floor of the elevator that is scanning for requests
	*/
	public int getClosestPendingRequest(int currentFloor) {
		int shortestDistance = Math.abs(currentFloor - requestList.get(0).getCallingFloor());
		int nearestFloor = requestList.get(0).getCallingFloor();
		for (int i = 1; i < requestList.size(); i++) {
			int distance = Math.abs(currentFloor - requestList.get(i).getCallingFloor());
			if (distance < shortestDistance) {
				shortestDistance = distance;
				nearestFloor = requestList.get(i).getCallingFloor();
			}			
		}
		return nearestFloor;
	}
	
	/**
	 * This method removes a request to a given floor from the queue.
	 * @param floor the floor of the request to remove
	 */
	public void removePendingRequest(int floor) {
		Request request = null;
		for (int i = 0; i < requestList.size(); i++) {
			request = requestList.get(i);
			if (request.getCallingFloor() == floor) {
				break;
			}
		}
		requestList.remove(request);
	}
}